wake-up-neo.net

Wie konvertiere ich eine DataTable in eine Zeichenfolge in C #?

Ich verwende Visual Studio 2005 und habe eine DataTable mit zwei Spalten und einigen Zeilen, die ich an die Konsole ausgeben möchte. Ich hoffte, dass es so etwas geben würde:

DataTable results = MyMethod.GetResults();
Console.WriteLine (results.ToString());

Was ist der beste Weg (d. H. Die geringste Codierung von mir), um eine einfache DataTable in einen String zu konvertieren?

23
Mark Allison

Sie könnten etwas wie this verwenden:

Private Sub PrintTableOrView(ByVal table As DataTable, ByVal label As String)
    Dim sw As System.IO.StringWriter
    Dim output As String

    Console.WriteLine(label)

    ' Loop through each row in the table. '
    For Each row As DataRow In table.Rows
        sw = New System.IO.StringWriter
        ' Loop through each column. '
        For Each col As DataColumn In table.Columns
            ' Output the value of each column's data.
            sw.Write(row(col).ToString() & ", ")
        Next
        output = sw.ToString
        ' Trim off the trailing ", ", so the output looks correct. '
        If output.Length > 2 Then
            output = output.Substring(0, output.Length - 2)
        End If
        ' Display the row in the console window. '
        Console.WriteLine(output)
    Next
    Console.WriteLine()
End Sub
6
Galwegian
string res = string.Join(Environment.NewLine, 
    results.Rows.OfType<DataRow>().Select(x => string.Join(" ; ", x.ItemArray)));
28
ericmas001

Spät aber das benutze ich

 public static string ConvertDataTableToString(DataTable dataTable)
    {
        var output = new StringBuilder();

        var columnsWidths = new int[dataTable.Columns.Count];

        // Get column widths
        foreach (DataRow row in dataTable.Rows)
        {
           for(int i = 0; i < dataTable.Columns.Count; i++)
           {
               var length = row[i].ToString().Length;
               if (columnsWidths[i] < length)
                   columnsWidths[i] = length;
           }     
        }

        // Get Column Titles
        for (int i = 0; i < dataTable.Columns.Count; i++)
        {
            var length = dataTable.Columns[i].ColumnName.Length;
               if (columnsWidths[i] < length)
                   columnsWidths[i] = length;
        }

        // Write Column titles
        for (int i = 0; i < dataTable.Columns.Count; i++)
        {
            var text = dataTable.Columns[i].ColumnName;
            output.Append("|" + PadCenter(text, columnsWidths[i] + 2));
        }
        output.Append("|\n" + new string('=', output.Length) + "\n");

        // Write Rows
        foreach (DataRow row in dataTable.Rows)
        {
            for (int i = 0; i < dataTable.Columns.Count; i++)
            {
                var text = row[i].ToString();
                output.Append("|" + PadCenter(text,columnsWidths[i] + 2));
            }
            output.Append("|\n");
        }
        return output.ToString();
    }

    private static string PadCenter(string text, int maxLength)
    {
        int diff = maxLength - text.Length;
        return new string(' ', diff/2) + text + new string(' ', (int) (diff / 2.0 + 0.5));

    } 
25
user1215839
using(var writer = new StringWriter()) {
    results.WriteXml(writer);
    Console.WriteLine(writer.ToString());
}

Natürlich hängt die Nützlichkeit davon davon ab, wie wichtig die Formatierung ist. Wenn es sich nur um einen Debug-Dump handelt, finde ich XML-Ausgaben wie diese sehr lesbar. Wenn jedoch die Formatierung für Sie wichtig ist, haben Sie keine andere Wahl, als Ihre eigene Methode zu schreiben.

14

ich weiß, dass ich Jahre später bin xD

    public static string convertDataTableToString(DataTable dataTable)
    {
        string data = string.Empty;
        for (int i = 0; i < dataTable.Rows.Count; i++)
        {
            DataRow row = dataTable.Rows[i];
            for (int j = 0; j < dataTable.Columns.Count; j++)
            {
                data += dataTable.Columns[j].ColumnName + "~" + row[j];
                if (j == dataTable.Columns.Count - 1)
                {
                    if (i != (dataTable.Rows.Count - 1))
                        data += "$";
                }
                else
                    data += "|";
            }
        }
        return data;
    }

Wenn jemand dies jemals optimiert, lass es mich wissen

ich habe das versucht:

    public static string convertDataTableToString(DataTable dataTable)
    {
        string data = string.Empty;
        int rowsCount = dataTable.Rows.Count;
        for (int i = 0; i < rowsCount; i++)
        {
            DataRow row = dataTable.Rows[i];
            int columnsCount = dataTable.Columns.Count;
            for (int j = 0; j < columnsCount; j++)
            {
                data += dataTable.Columns[j].ColumnName + "~" + row[j];
                if (j == columnsCount - 1)
                {
                    if (i != (rowsCount - 1))
                        data += "$";
                }
                else
                    data += "|";
            }
        }
        return data;
    }

aber diese Antwort sagt, es ist schlimmer

4
Shereef Marzouk

Ich würde PowerShell installieren. Es versteht .NET-Objekte und hat eine Format-Tabelle und eine Export-Csv, die genau was Sie suchen. Wenn Sie irgendeine Art von Konsolenarbeit ausführen, ist dies eine großartige Ergänzung/Ersatz für C # -Konsolen-Apps. 

Als ich damit anfing, schrieb ich meine Konsolen-Apps als Bibliotheken um und importierte die Bibliotheken in Powershell. Die integrierten Commandlets machen die Arbeit der Konsole so schön. 

3
jwmiller5

zwei für Schleifen, eine für Zeilen, eine andere für Spalten, Ausgabe Achten Sie auf Nullen und DbNulls.

2
Petar Repac

Oder ändern Sie die App in WinForms, verwenden Sie ein Raster und binden Sie DataTable an das Raster. Wenn es sich um eine Demo/Beispiel-App handelt.

1
Petar Repac
    /// <summary>
    /// Dumps the passed DataSet obj for debugging as list of html tables
    /// </summary>
    /// <param name="msg"> the msg attached </param>
    /// <param name="ds"> the DataSet object passed for Dumping </param>
    /// <returns> the Nice looking dump of the DataSet obj in html format</returns>
    public static string DumpHtmlDs(string msg, ref System.Data.DataSet ds)
    {
        StringBuilder objStringBuilder = new StringBuilder();
        objStringBuilder.AppendLine("<html><body>");

        if (ds == null)
        {
            objStringBuilder.AppendLine("Null dataset passed ");
            objStringBuilder.AppendLine("</html></body>");
            WriteIf(objStringBuilder.ToString());
            return objStringBuilder.ToString();
        }

        objStringBuilder.AppendLine("<p>" + msg + " START </p>");
        if (ds != null)
        {
            if (ds.Tables == null)
            {
                objStringBuilder.AppendLine("ds.Tables == null ");
                return objStringBuilder.ToString();
            }


            foreach (System.Data.DataTable dt in ds.Tables)
            {

                if (dt == null)
                {
                    objStringBuilder.AppendLine("ds.Tables == null ");
                    continue;
                }
                objStringBuilder.AppendLine("<table>");

                //objStringBuilder.AppendLine("================= My TableName is  " +
                //dt.TableName + " ========================= START");
                int colNumberInRow = 0;
                objStringBuilder.Append("<tr><th>row number</th>");
                foreach (System.Data.DataColumn dc in dt.Columns)
                {
                    if (dc == null)
                    {
                        objStringBuilder.AppendLine("DataColumn is null ");
                        continue;
                    }


                    objStringBuilder.Append(" <th> |" + colNumberInRow.ToString() + " | ");
                    objStringBuilder.Append(  dc.ColumnName.ToString() + " </th> ");
                    colNumberInRow++;
                } //eof foreach (DataColumn dc in dt.Columns)
                objStringBuilder.Append("</tr>");

                int rowNum = 0;
                foreach (System.Data.DataRow dr in dt.Rows)
                {
                    objStringBuilder.Append("<tr><td> row - | " + rowNum.ToString() + " | </td>");
                    int colNumber = 0;
                    foreach (System.Data.DataColumn dc in dt.Columns)
                    {
                        objStringBuilder.Append(" <td> |" + colNumber + "|" );
                        objStringBuilder.Append(dr[dc].ToString() + "  </td>");
                        colNumber++;
                    } //eof foreach (DataColumn dc in dt.Columns)
                    rowNum++;
                    objStringBuilder.AppendLine(" </tr>");
                }   //eof foreach (DataRow dr in dt.Rows)

                objStringBuilder.AppendLine("</table>");
                objStringBuilder.AppendLine("<p>" + msg + " END </p>");
            }   //eof foreach (DataTable dt in ds.Tables)

        } //eof if ds !=null 
        else
        {

            objStringBuilder.AppendLine("NULL DataSet object passed for debugging !!!");
        }
        return objStringBuilder.ToString();

    } 
1
Yordan Georgiev

sehr vage ....

ich habe es einfach in einen Datensatz gepackt, damit ich es einfach als XML ausgeben kann ....

wenn dies nicht der Fall ist, iterieren Sie nicht durch seine Zeilen- und Spaltensammlungen und geben Sie sie aus.

0
John Nicholas

Ich habe meine Klassenvariante für Ihre Bedürfnisse erstellt. Ich glaube, es ist ein bisschen konfigurierbarer als bereits zur Verfügung gestellte Varianten. Sie können es mit allen Standardeinstellungen verwenden, indem Sie einfach eine Instanz einer Klasse erstellen und die StringifyDataTable-Methode aufrufen oder bei Bedarf zusätzliche Optionen festlegen.

public class DataTableStringifier
{
    public bool IsOuterBordersPresent { get; set; } //Whether outer borders of table needed
    public bool IsHeaderHorizontalSeparatorPresent { get; set; } // Whether horizontal line separator between table title and data is needed. Useful to set 'false' if you expect only 1 or 2 rows of data - no need for additional lines then
    public char ValueSeparator { get; set; } //Vertical line character
    public char HorizontalLinePadChar { get; set; } // Horizontal line character
    public char HorizontalLineSeparator { get; set; } // Horizontal border (between header and data) column separator (crossing of horizontal and vertical borders)
    public int ValueMargin { get; set; } // Horizontal margin from table borders (inner and outer) to cell values
    public int MaxColumnWidth { get; set; } // To avoid too wide columns with thousands of characters. Longer values will be cropped in the center
    public string LongValuesEllipses { get; set; } // Cropped values wil be inserted this string in the middle to mark the point of cropping

    public DataTableStringifier()
    {
        MaxColumnWidth = int.MaxValue;
        IsHeaderHorizontalSeparatorPresent = true;
        ValueSeparator = '|';
        ValueMargin = 1;
        HorizontalLinePadChar = '-';
        HorizontalLineSeparator = '+';
        LongValuesEllipses = "...";
        IsOuterBordersPresent = false;
    }

    public string StringifyDataTable(DataTable table)
    {
        int colCount = table.Columns.Count;
        int rowCount = table.Rows.Count;
        string[] colHeaders = new string[colCount];
        string[,] cells = new string[rowCount, colCount];
        int[] colWidth = new int[colCount];

        for (int i = 0; i < colCount; i++)
        {
            var column = table.Columns[i];
            var colName = ValueToLimitedLengthString(column.ColumnName);
            colHeaders[i] = colName;
            if (colWidth[i] < colName.Length)
            {
                colWidth[i] = colName.Length;
            }
        }

        for (int i = 0; i < rowCount; i++)
        {
            DataRow row = table.Rows[i];
            for (int j = 0; j < colCount; j++)
            {
                var valStr = ValueToLimitedLengthString(row[j]);
                cells[i, j] = valStr;
                if (colWidth[j] < valStr.Length)
                {
                    colWidth[j] = valStr.Length;
                }
            }
        }

        string valueSeparatorWithMargin = string.Concat(new string(' ', ValueMargin), ValueSeparator, new string(' ', ValueMargin));
        string leftBorder = IsOuterBordersPresent ? string.Concat(ValueSeparator, new string(' ', ValueMargin)) : "";
        string rightBorder = IsOuterBordersPresent ? string.Concat(new string(' ', ValueMargin), ValueSeparator) : "";
        string horizLine = new string(HorizontalLinePadChar, colWidth.Sum() + (colCount - 1)*(ValueMargin*2 + 1) + (IsOuterBordersPresent ? (ValueMargin + 1)*2 : 0));

        StringBuilder tableBuilder = new StringBuilder();

        if (IsOuterBordersPresent)
        {
            tableBuilder.AppendLine(horizLine);
        }

        tableBuilder.Append(leftBorder);
        for (int i = 0; i < colCount; i++)
        {
            tableBuilder.Append(colHeaders[i].PadRight(colWidth[i]));
            if (i < colCount - 1)
            {
                tableBuilder.Append(valueSeparatorWithMargin);
            }
        }
        tableBuilder.AppendLine(rightBorder);

        if (IsHeaderHorizontalSeparatorPresent)
        {
            if (IsOuterBordersPresent)
            {
                tableBuilder.Append(ValueSeparator);
                tableBuilder.Append(HorizontalLinePadChar, ValueMargin);
            }
            for (int i = 0; i < colCount; i++)
            {
                tableBuilder.Append(new string(HorizontalLinePadChar, colWidth[i]));
                if (i < colCount - 1)
                {
                    tableBuilder.Append(HorizontalLinePadChar, ValueMargin);
                    tableBuilder.Append(HorizontalLineSeparator);
                    tableBuilder.Append(HorizontalLinePadChar, ValueMargin);
                }
            }
            if (IsOuterBordersPresent)
            {
                tableBuilder.Append(HorizontalLinePadChar, ValueMargin);
                tableBuilder.Append(ValueSeparator);
            }
            tableBuilder.AppendLine();
        }

        for (int i = 0; i < rowCount; i++)
        {
            tableBuilder.Append(leftBorder);
            for(int j=0; j<colCount; j++)
            {
                tableBuilder.Append(cells[i, j].PadRight(colWidth[j]));
                if(j<colCount-1)
                {
                    tableBuilder.Append(valueSeparatorWithMargin);
                }
            }
            tableBuilder.AppendLine(rightBorder);
        }

        if (IsOuterBordersPresent)
        {
            tableBuilder.AppendLine(horizLine);
        }

        return tableBuilder.ToString(0, tableBuilder.Length - 1); //Trim last enter char
    }

    private string ValueToLimitedLengthString(object value)
    {
        string strValue = value.ToString();
        if (strValue.Length > MaxColumnWidth)
        {
            int beginningLength = (MaxColumnWidth) / 2;
            int endingLength = (MaxColumnWidth + 1) / 2 - LongValuesEllipses.Length;
            return string.Concat(strValue.Substring(0, beginningLength), LongValuesEllipses, strValue.Substring(strValue.Length - endingLength, endingLength));
        }
        else
        {
            return strValue;
        }
    }
}
public static string DataTable2String(DataTable dataTable)
{
    StringBuilder sb = new StringBuilder();
    if (dataTable != null)
    {
        string seperator = " | ";

        #region get min length for columns
        Hashtable hash = new Hashtable();
        foreach (DataColumn col in dataTable.Columns)
            hash[col.ColumnName] = col.ColumnName.Length;
        foreach (DataRow row in dataTable.Rows)
            for (int i = 0; i < row.ItemArray.Length; i++)
                if (row[i] != null)
                    if (((string)row[i]).Length > (int)hash[dataTable.Columns[i].ColumnName])
                        hash[dataTable.Columns[i].ColumnName] = ((string)row[i]).Length;
        int rowLength = (hash.Values.Count + 1) * seperator.Length;
        foreach (object o in hash.Values)
            rowLength += (int)o;
        #endregion get min length for columns

        sb.Append(new string('=', (rowLength - " DataTable ".Length) / 2));
        sb.Append(" DataTable ");
        sb.AppendLine(new string('=', (rowLength - " DataTable ".Length) / 2));
        if (!string.IsNullOrEmpty(dataTable.TableName))
            sb.AppendLine(String.Format("{0,-" + rowLength + "}", String.Format("{0," + ((rowLength + dataTable.TableName.Length) / 2).ToString() + "}", dataTable.TableName)));

        #region write values
        foreach (DataColumn col in dataTable.Columns)
            sb.Append(seperator + String.Format("{0,-" + hash[col.ColumnName] + "}", col.ColumnName));
        sb.AppendLine(seperator);
        sb.AppendLine(new string('-', rowLength));
        foreach (DataRow row in dataTable.Rows)
        {
            for (int i = 0; i < row.ItemArray.Length; i++)
            {
                sb.Append(seperator + String.Format("{0," + hash[dataTable.Columns[i].ColumnName] + "}", row[i]));
                if (i == row.ItemArray.Length - 1)
                    sb.AppendLine(seperator);
            }
        }
        #endregion write values

        sb.AppendLine(new string('=', rowLength));
    }
    else
        sb.AppendLine("================ DataTable is NULL ================");

    return sb.ToString();
}

ausgabe:

======================= DataTable =======================
                         MyTable                          
 | COL1 | COL2                    | COL3 1000000ng name | 
----------------------------------------------------------
 |    1 |                       2 |                   3 | 
 |  abc | Dienstag, 12. März 2013 |                 xyz | 
 | Have |                  a Nice |                day! | 
==========================================================
0
pr0gg3r

Wenn Sie eine einzelne Spalte in datatable haben, ist es einfach, datatable in string zu ändern.

DataTable results = MyMethod.GetResults();
if(results != null && results.Rows.Count > 0)  // Check datatable is null or not
{
  List<string> lstring = new List<string>();
  foreach(DataRow dataRow in dt.Rows)
  {
     lstring.Add(Convert.ToString(dataRow["ColumnName"]));
  }
  string mainresult = string.Join(",", lstring.ToArray()); // You can Use comma(,) or anything which you want. who connect the two string. You may leave space also.
}
Console.WriteLine (mainresult);
0
Love Pandey